CVE-2026-34151 XWiki Platform: Resource path traversal via /skin/ action endpoint in Jetty 12+
Unauthenticated attackers can read arbitrary files via path traversal in XWiki when running on Jetty 12+, exposing sensitive configuration and host files.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-34151?
CVE-2026-34151 is a high-severity path traversal vulnerability in xwiki-platform, published on 14 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
XWiki Platform is a generic wiki platform. Prior to 17.10.5 and 18.2.0, the /skin/ action in com.xpn.xwiki.web.SkinAction can resolve double-encoded parent-directory segments outside the intended skin or web-application resource prefix when Jetty 12 or later decodes the request path. The affected lookup is replaced with Environment.getResourceAsStream(String, String), which constrains a resource to its expected prefix. An unauthenticated remote attacker can use the vulnerable behavior to read arbitrary resources permitted to the Jetty process, including WEB-INF/xwiki.cfg and, depending on deployment depth and operating-system permissions, host files. Tomcat and Jetty versions before 12 do not appear affected. This issue is fixed in versions 17.10.5 and 18.2.0.
Weakness: CWE-24
Which versions are affected by CVE-2026-34151?
4 open source packages ship an affected version, including org.xwiki.platform:xwiki-platform-oldcore.
| Package | Affected | Fixed in |
|---|---|---|
org.xwiki.platform:xwiki-platform-oldcore Maven | All versions | 17.10.5 |
org.xwiki.platform:xwiki-platform-oldcore Maven | All versions | 17.10.5 |
org.xwiki.platform:xwiki-platform-oldcore Maven | From 18.0.0-rc-1 | 18.2.0 |
org.xwiki.platform:xwiki-platform-oldcore Maven | From 18.0.0-rc-1 | 18.2.0 |
How do I fix CVE-2026-34151?
Upgrade org.xwiki.platform:xwiki-platform-oldcore to a fixed version for your release line: 17.10.5 or 18.2.0.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-34151 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-34151 exists.
Public exploit code: 1 Nuclei template.
Sources
Also known as GHSA-qj4x-9g63-25g6.